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Diffstat (limited to 'gc/include/gc_mark.h')
| -rw-r--r-- | gc/include/gc_mark.h | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/gc/include/gc_mark.h b/gc/include/gc_mark.h deleted file mode 100644 index 0856d16..0000000 --- a/gc/include/gc_mark.h +++ /dev/null @@ -1,145 +0,0 @@ -/* - * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. - * Copyright (c) 2001 by Hewlett-Packard Company. All rights reserved. - * - * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED - * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. - * - * Permission is hereby granted to use or copy this program - * for any purpose, provided the above notices are retained on all copies. - * Permission to modify the code and to distribute modified code is granted, - * provided the above notices are retained, and a notice that the code was - * modified is included with the above copyright notice. - * - */ - -/* - * This contains interfaces to the GC marker that are likely to be useful to - * clients that provide detailed heap layout information to the collector. - * This interface should not be used by normal C or C++ clients. - * It will be useful to runtimes for other languages. - * - * Note that this file is not "namespace-clean", i.e. it introduces names - * not prefixed with GC_, which may collide with the client's names. It - * should be included only in those few places that directly provide - * information to the collector. - */ -#ifndef GC_MARK_H -# define GC_MARK_H - -# ifndef GC_H -# include "gc.h" -# endif - -/* A client supplied mark procedure. Returns new mark stack pointer. */ -/* Primary effect should be to push new entries on the mark stack. */ -/* Mark stack pointer values are passed and returned explicitly. */ -/* Global variables decribing mark stack are not necessarily valid. */ -/* (This usually saves a few cycles by keeping things in registers.) */ -/* Assumed to scan about GC_PROC_BYTES on average. If it needs to do */ -/* much more work than that, it should do it in smaller pieces by */ -/* pushing itself back on the mark stack. */ -/* Note that it should always do some work (defined as marking some */ -/* objects) before pushing more than one entry on the mark stack. */ -/* This is required to ensure termination in the event of mark stack */ -/* overflows. */ -/* This procedure is always called with at least one empty entry on the */ -/* mark stack. */ -/* Currently we require that mark procedures look for pointers in a */ -/* subset of the places the conservative marker would. It must be safe */ -/* to invoke the normal mark procedure instead. */ -/* WARNING: Such a mark procedure may be invoked on an unused object */ -/* residing on a free list. Such objects are cleared, except for a */ -/* free list link field in the first word. Thus mark procedures may */ -/* not count on the presence of a type descriptor, and must handle this */ -/* case correctly somehow. */ -# define GC_PROC_BYTES 100 -struct GC_ms_entry; -typedef struct GC_ms_entry * (*GC_mark_proc) GC_PROTO(( - GC_word * addr, struct GC_ms_entry * mark_stack_ptr, - struct GC_ms_entry * mark_stack_limit, GC_word env)); - -# define GC_LOG_MAX_MARK_PROCS 6 -# define GC_MAX_MARK_PROCS (1 << GC_LOG_MAX_MARK_PROCS) - -/* In a few cases it's necessary to assign statically known indices to */ -/* certain mark procs. Thus we reserve a few for well known clients. */ -/* (This is necessary if mark descriptors are compiler generated.) */ -#define GC_RESERVED_MARK_PROCS 8 -# define GC_GCJ_RESERVED_MARK_PROC_INDEX 0 - -/* Object descriptors on mark stack or in objects. Low order two */ -/* bits are tags distinguishing among the following 4 possibilities */ -/* for the high order 30 bits. */ -#define GC_DS_TAG_BITS 2 -#define GC_DS_TAGS ((1 << GC_DS_TAG_BITS) - 1) -#define GC_DS_LENGTH 0 /* The entire word is a length in bytes that */ - /* must be a multiple of 4. */ -#define GC_DS_BITMAP 1 /* 30 (62) bits are a bitmap describing pointer */ - /* fields. The msb is 1 iff the first word */ - /* is a pointer. */ - /* (This unconventional ordering sometimes */ - /* makes the marker slightly faster.) */ - /* Zeroes indicate definite nonpointers. Ones */ - /* indicate possible pointers. */ - /* Only usable if pointers are word aligned. */ -#define GC_DS_PROC 2 - /* The objects referenced by this object can be */ - /* pushed on the mark stack by invoking */ - /* PROC(descr). ENV(descr) is passed as the */ - /* last argument. */ -# define GC_MAKE_PROC(proc_index, env) \ - (((((env) << GC_LOG_MAX_MARK_PROCS) \ - | (proc_index)) << GC_DS_TAG_BITS) | GC_DS_PROC) -#define GC_DS_PER_OBJECT 3 /* The real descriptor is at the */ - /* byte displacement from the beginning of the */ - /* object given by descr & ~DS_TAGS */ - /* If the descriptor is negative, the real */ - /* descriptor is at (*<object_start>) - */ - /* (descr & ~DS_TAGS) - GC_INDIR_PER_OBJ_BIAS */ - /* The latter alternative can be used if each */ - /* object contains a type descriptor in the */ - /* first word. */ - /* Note that in multithreaded environments */ - /* per object descriptors maust be located in */ - /* either the first two or last two words of */ - /* the object, since only those are guaranteed */ - /* to be cleared while the allocation lock is */ - /* held. */ -#define GC_INDIR_PER_OBJ_BIAS 0x10 - -extern GC_PTR GC_least_plausible_heap_addr; -extern GC_PTR GC_greatest_plausible_heap_addr; - /* Bounds on the heap. Guaranteed valid */ - /* Likely to include future heap expansion. */ - -/* Handle nested references in a custom mark procedure. */ -/* Check if obj is a valid object. If so, ensure that it is marked. */ -/* If it was not previously marked, push its contents onto the mark */ -/* stack for future scanning. The object will then be scanned using */ -/* its mark descriptor. */ -/* Returns the new mark stack pointer. */ -/* Handles mark stack overflows correctly. */ -/* Since this marks first, it makes progress even if there are mark */ -/* stack overflows. */ -/* Src is the address of the pointer to obj, which is used only */ -/* for back pointer-based heap debugging. */ -/* It is strongly recommended that most objects be handled without mark */ -/* procedures, e.g. with bitmap descriptors, and that mark procedures */ -/* be reserved for exceptional cases. That will ensure that */ -/* performance of this call is not extremely performance critical. */ -/* (Otherwise we would need to inline GC_mark_and_push completely, */ -/* which would tie the client code to a fixed colllector version.) */ -struct GC_ms_entry *GC_mark_and_push - GC_PROTO((GC_PTR obj, - struct GC_ms_entry * mark_stack_ptr, - struct GC_ms_entry * mark_stack_limit, GC_PTR *src)); - -#define GC_MARK_AND_PUSH(obj, msp, lim, src) \ - (((GC_word)obj >= (GC_word)GC_least_plausible_heap_addr && \ - (GC_word)obj <= (GC_word)GC_greatest_plausible_heap_addr)? \ - GC_mark_and_push(obj, msp, lim, src) : \ - msp) - -#endif /* GC_MARK_H */ - |